Hi, I did some further testing.
Now I would say that the core problem is that one cannot start more than one X server on secondary seats. The X server fails to start with a DRM-related error like this: [ 1716.627] (EE) intel(0): [drm] failed to set drm interface version: Permission denied [13]. [ 1716.627] (EE) intel(0): Failed to claim DRM device. [ 1716.627] (II) UnloadModule: "intel" [ 1716.627] (EE) Screen(s) found, but none have a usable configuration. The kernel log shows nothing related. All other effects would be IMHO results of this problem. A simple test consists of starting another X server with the same command line options (except the DISPLAY) as started by the display manager. I tried various combinations between Intel chipset graphics, NVidia and AMD graphics cards. No matter which of those I put as primary, the secondary always shows this problem. I also tried the same on vivid and even on Fedora 21 which both have more recent software version but exhibit the same problem. In conclusion I would say that both lightdm and light-locker do the right thing. Do you have any advice about how to work on this DRM problem or at least where to report it? I also tried Ubuntu instead of Xubuntu and was surprised to find out that Ubuntu works much better for my scenario. Unity locks sessions from within and also shows a password dialog thereby supporting secondary seats much better than Xubuntu with light-locker. Unity also does not offer to switch to other users on the secondary screen, which again fits me better. On 1 January 2015 at 03:07, Richard Hansen <[email protected]> wrote: > On 12/31/2014 08:13 PM, Schlomo Schapiro wrote: > > Hi, > > > > see https://bugs.launchpad.net/ubuntu/+source/lightdm/+bug/1406834 > > Looks like you have two problems that I'm guessing are unrelated: > > * Scenario #1: When using xscreensaver, locking works but LightDM > keeps trying and failing to spawn a greeter on non-seat0 seats > while the screen is in power-save mode. > * Scenario #2: When using light-locker, locking on non-seat0 seats > doesn't properly session-switch to LightDM. > > You filed a bug report for scenario #1; would you please also file a bug > report for scenario #2 (against light-locker)? > AFAIKT light-locker works fine provided one can start another X server. In light of the current state of that I would say that the design decision of light-locker was correct but premature. > On 1 January 2015 at 01:34, Richard Hansen <[email protected]> > > wrote: > >> > >> Support for session switching on non-seat0 seats was added in systemd > >> 208 [1] and xorg-server 1.16 [2], both of which are available in utopic > >> (but not trusty). > >> > >> [1] > http://cgit.freedesktop.org/systemd/systemd/commit/?id=d7bd01b547bd91353513131561de9cc7d9f7d405 > >> [2] > http://cgit.freedesktop.org/xorg/xserver/commit/?id=cac39219898f5e5a59ff8d8d6524f5fe0d111469 > > > > Very very cool. So now I found out that it does not work for me. > > I should mention that I have never tried utopic (I'm still running > trusty) so I don't know if session switching on non-seat0 seats would > work for me either. > > > The question is why. I guess I'll try also with different graphics cards > > to find out if it is related to the radeon driver. > > By "radeon driver" I assume you mean the open source radeon driver and > not the proprietary fglrx driver, right? > Yes, at least with the proprietary NVidia driver second seats seem impossible. My card is too old to be supported by the fglrx driver. > > >>> It seems to me rather that light-locker just locks the session with the > >>> "This session is locked" but then lightdm cannot show the greeter > >>> anywhere to ask for a passwort to unlock it. > >> > >> Yes; seems like something is trying to switch sessions but failing > >> somehow. Anything interesting in lightdm or X logs? > > > > Yes, see above bug report. lightdm.log is now 1.4 GB after just a few > > hours... > > What about scenario #2 (using light-locker)? > > >>> and that after logging out > >>> of the session there is no new login screen. Apparently lightdm does > not > >>> start a new session on this seat after the first session is done. > >> > >> That seems odd to me, and sounds like a lightdm bug... Do the lightdm > >> logs show anything interesting? > > > > Yes, it fails to start another X server. I guess that in my case (using > > xscreensaver instead of light-locker), I would expect this not to happen > > unless it is doing it in order to offer another login for user switching. > > Whenever you log out, the X server is supposed to exit -- that's normal > behavior. The display manager (LightDM) is then supposed to spawn a new > X instance. > > What happens when you set allow-user-switching=false, switch to > light-locker, log in to seat-1, then log out? Does it still fail? What > are the symptoms exactly? Anything interesting in the logs? > I think that maybe here is an issue with lightdm as in that case the logs would just say that the session finished and nothing more. Is there a real debug mode for lightdm that reveals the internal decision processes? > > >> But it should, given that utopic should support session switching on > >> non-seat0 seats. I would expect trusty to have problems, but not > utopic. > > > > I see. Against which package(s) should I report this as a bug? > > light-locker > > > Is this an "official" feature of utopic? > > I don't know if any Ubuntu release has any "official" features, but > certainly there are some features Canonical cares more about than > others. I don't think multiseat is high on their list of priorities. > Sad indeed. It is such a cool feature and starts to work really well now. > > However, session switching on non-seat0 seats is a feature of logind > v208 and X server v1.16, and those are in utopic, so if it's not working > then it's a bug in utopic that should be addressed. And it will be > addressed if there's enough manpower to troubleshoot, fix, and test > (which is where volunteers like us come in). > See above, seems to be not related to light* but to X and maybe systemd. A hint against which packages to report would help me and I would gladly report that. Kind Regards, Schlomo
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